Jacob "Jack" Lew's signature, on the 2012 "Mid-Session Review" of the federal budget. He was director of the Office of Management and Budget at the time.

WhiteHouse.gov

Saying he "cannot think of a better person" to take the job, President Obama this afternoon formally announced he is nominating Jacob "Jack" Lew, his chief of staff, to be the next Treasury secretary.

Word of Obama's decision to tap Lew, who previously served as budget director in the Obama and Clinton administration, broke Wednesday.

"Jack has my complete trust," Obama said.

Of Geithner, the president said, "when the history books are written, Tim Geithner's going to go down as one of the finest secretaries of the Treasury." When they came to office in 2009, Obama said, the nation was in the midst of a financial crisis, "bank after bank was on the verge of collapse" and 800,000 jobs had been lost in one month. "I couldn't blame Tim when he tried to tell me he wasn't the right guy for the job," Obama joked.

Lew said he looks forward to the challenge of being Treasury secretary, and made a joking reference to his unusual signature (which we posted about Wednesday). "We both share a common challenge in penmanship," he said to Geithner.

Then, at the end of the event, the president got in his own dig at Lew's loopy John Handcock.

"I'd never noticed Jack's signature," he said, until it was "highlighted yesterday in the press. I considered rescinding [the nomination]." But, Obama added, Lew has promised to work on "at least making one letter legible in order not to debate our currency."